1. Field of the Invention
The invention related generally to nasal drug delivery. More specifically, the invention is a device and method for direct drug delivery primarily to nasal surfaces while minimizing drug delivery to the lungs and trachea.
2. Description of Related Art
Known nasal delivery systems use one of three methods: Natural Inspiration, Pressurized Delivery, and Bidirectional Delivery. Natural Inspiration delivers aerosol through a face mask and the subject inhales the aerosol. Pressurized Delivery sprays an aerosol into a nostril, or nasal nare, using positive pressure. Bidirectional Delivery requires the subject to blow into a nasal injector device, which causes the soft palette to close. Positive pressure produced by the subject blowing into the device injects aerosol into one nostril and into the nasal cavity. The use of a subject's breath to generate positive pressure, however, prevents reuse of the device by other subjects because of possible cross-contamination.
The known nasal aerosol delivery systems suffer from a number of limitations including the deposition of aerosol in the external nares, limited aerosol delivery beyond the nasal valve and onto internal nasal surfaces, and aerosol flow recirculation causing backflow into the nasal cavity, swallowing, and/or inhalation of aerosol. These limitations lead to inconsistencies in the effective dose of aerosol delivered using these methods.